Laminaria longicruris
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''Laminaria'' is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of
brown seaweed Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and p ...
in the order
Laminariales Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms. Kelp grows in "underwat ...
(kelp), comprising 31
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relatively large size. Some species are called Devil's apron, due to their shape, or sea colander, due to the perforations present on the
lamina Lamina may refer to: Science and technology * Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics * Laminar flow, (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption betwee ...
. Others are referred to as ''tangle''. ''Laminaria'' form a habitat for many fish and invertebrates. The life cycle of ''Laminaria'' has heteromorphic
alternation of generations Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of life cycle in plants and algae. It consists of a multicellular haploid sexual phase, the gametophyte, which has a single set of chromosomes alt ...
which differs from ''
Fucus ''Fucus'' is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world. Description and life cycle The thallus is perennial with an irregular or disc-shaped holdfast or with haptera. The erect portion o ...
''. At meiosis the male and female zoospores are produced separately, then germinate into male and female gametophytes. The female egg matures in the
oogonium An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in l ...
until the male sperm fertilizes it. Life-Cycle: The most apparent form of ''Laminaria'' is its sporophyte phase, a structure composed of the holdfast, the stipe, and the blades. While it spends its time predominately in the sporophyte phase, it alternates between the sporophyte and its microscopic gametophyte phase. ''Laminaria japonica'' (J. E. Areschoug – Japón) is now regarded as a synonym of ''
Saccharina japonica ''Saccharina japonica'' is a marine species of the Phaeophyceae (brown algae) class, a type of kelp or seaweed, which is extensively cultivated on ropes between the seas of China, Japan and Korea. It has the common name sweet kelp. It is wi ...
'' and ''Laminaria saccharina'' is now classified as ''
Saccharina latissima ''Saccharina latissima'' is a brown alga (class Phaeophyceae), of the family Laminariaceae. It is known by the common names sugar kelp, sea belt, and Devil's apron, and is one of the species known to Japanese cuisine as kombu. It is found in t ...
''.


History

''Laminaria'' arrived in China from Hokkaido, Japan in the late 1920s. Once in China, ''Laminaria'' was cultivated on a much larger industrial scale.Culture of Kelp (Laminaria japonica) in China. FAO. June 1989. The rocky shores at Dalian, the northern coast of the
Yellow Sea The Yellow Sea is a marginal sea of the Western Pacific Ocean located between mainland China and the Korean Peninsula, and can be considered the northwestern part of the East China Sea. It is one of four seas named after common colour ter ...
, along with its cold waters provided excellent growing conditions for these species. ''Laminaria'' was harvested for food and 1949 yielded 40.3 metric tons of dry weight. ''Laminaria'' need cold water to survive and can only live above 36° N latitude. In 1949, the Chinese started to commercially grow ''laminaria'' as a crop. This increased the production of dry weight to 6,200 metric tons. Farming ''laminaria'' is still a large production for China. However, since the 1980s production has dropped due to new
mariculture Mariculture or marine farming is a specialized branch of aquaculture (which includes freshwater aquaculture) involving the cultivation of marine organisms for food and other animal products, in enclosed sections of the open ocean ( offshore m ...
technology .


Farming practices

''Laminaria'' is generally farmed using the floating raft method, in which young ''laminaria'' sporophytes are attached to submerged ropes. These ropes are then attached to floating rafts.


Ecology

''Laminaria'' is found in colder ocean waters, such as arctic regions. Preferring to stay in regions where there are rocky shores, this allows the ''laminaria'' to attach. Due to the height of the ''Laminaria'', they provide protection for creatures that the open ocean does not often give. Invertebrates are just one of the organisms that live among the algae. Sea snails and other invertebrates feed on the blades (leaves) of the ''laminaria''. Other organisms, such as sea urchins, feed on the holdfasts, which can kill the algae.
Red sea urchin The red sea urchin (''Mesocentrotus franciscanus'') is a sea urchin found in the northeastern Pacific Ocean from Alaska to Baja California. It lives in shallow waters from the low-tide line to greater than deep, and is typically found on rocky ...
s, found on the North America Pacific Coast, can decimate kelp, including ''Laminaria,'' if the urchins are not managed by
sea otter The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel family, but among the smal ...
s. Species such as ''
Coelopa pilipes ''Coelopa pilipes'' (common name kelp fly or seaweed fly) is a common European species of kelp fly. It was described by A. H. Haliday in 1838. Their appearance differs greatly from that of other '' Coelopa'' flies. ''C. pilipes'' are especi ...
'' feed and lay eggs on ''Laminaria'' when it is washed up on beaches.


Life cycle

''Laminaria'' expresses a haplo-diplophasic life history, in which it alternates from a macroscopic thallic
sporophyte A sporophyte () is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase. Life cycle The sporophyte develops from the zygote ...
structure, consisting of the holdfast, a stipe, and the blades, to a filamentous, microscopic
gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the ...
. The sporophyte structure of ''laminaria'' can grow to , which is large in comparison to other algae, but still smaller than the giant kelps such as
Macrocystis ''Macrocystis'' is a monospecific genus of kelp (large brown algae). This genus contains the largest of all the phaeophyceae or brown algae. ''Macrocystis'' has pneumatocysts at the base of its blades. Sporophytes are perennial and the indi ...
and
Nereocystis ''Nereocystis'' (Greek, 'mermaid's bladder') is a monotypic genus of subtidal kelp containing the species ''Nereocystis luetkeana''. Some English names include edible kelp, bull kelp, bullwhip kelp, ribbon kelp, bladder wrack, and variations of ...
, which can grow up to . On the other hand, the gametophyte structure is no more than a few millimeters in length. In opposition to the gametophyte phase, which only consists of one type of tissue, the more complex sporophyte phase is made up of different types of tissue. One of these tissues includes a sieve-like element which translocates
photoassimilate In botany, a photoassimilate is one of a number of biological compounds formed by assimilation using light-dependent reactions. This term is most commonly used to refer to the energy-storing monosaccharides produced by photosynthesis in the leaves ...
s. These structures are very similar to
mesophyll cell A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...
s found in higher plant leaves.


Uses


Medical

A
laminaria stick Osmotic dilators are medical implements used to dilate the uterine cervix by swelling as they absorb fluid from surrounding tissue. They may be composed of natural or synthetic materials. A laminaria stick or tent is a thin rod made of the stems o ...
may be used to slowly dilate the cervix to induce labor and delivery, or for surgical procedures including abortions or to facilitate the placement of an
intrauterine device An intrauterine device (IUD), also known as intrauterine contraceptive device (IUCD or ICD) or coil, is a small, often T-shaped birth control device that is inserted into the uterus to prevent pregnancy. IUDs are one form of long-acting revers ...
. The stick is made up of a bundle of dried and compressed laminaria that expands as water is absorbed. ''Laminaria'' is a source of the relatively rare element,
iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...
, which is commonly used to promote thyroid health. Certain carbohydrates such as mannitol, ''laminarin'', and alginate can be extracted from ''laminaria''.
Mannitol Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lo ...
is used to decrease high
intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated t ...
, and to lower excessive
intracranial pressure Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury ( mmHg) and at rest, is normally 7–15 mmHg for a supine adul ...
.
Laminarin The molecule laminarin (also known as laminaran) is a storage glucan (a polysaccharide of glucose) found in brown algae. It is used as a carbohydrate food reserve in the same way that chrysolaminarin is used by phytoplankton, especially in diato ...
has two forms, soluble and insoluble. The soluble form of ''Laminarin'' has high antitumor activity, can be used in the treatment of antibiotic-resistant nosocomial infections, can aid in normalizing enteric metabolism, helps to improve enzymatic processes of the intestine and does not possess antigenic or pyrogenic properties. ''Laminarin'' continues to be of active study in today's medical field.


Food

Various species of ''Laminaria'' have been used for food purposes since ancient times wherever humans have encountered them. Typically, the prepared parts, usually the blade, are consumed either immediately after boiling in broth or water, or consumed after drying. The greater proportion of commercial cultivation is for
algin Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. With metals such as sodium and calcium, its salts are known as alginates. Its colour ...
,
iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...
, and
mannitol Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lo ...
, which are used in a range of industrial applications. In
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
it is processed into a sweetmeat known as ''laminaria jelly'', in other countries it is also used in fresh salad form, which is also canned for preservation for deliverу and selling purposes in other regions. Many countries produce and consume laminaria products, the largest being
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
.


Energy

Due to their ability to grow underwater and in salt water, algae are being looked into as a source of
biofuel Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. According to the United States Energy Information Administration ...
. ''Laminaria'' is one of the five macroalgae farmed for products such as food, chemicals and power. Those five genera contribute to 76% of the total tonnage for farmed macroalgae. ''Laminaria'' is less desired as a renewable energy source due to its high ash content when burned. ''Laminaria'' has an ash content of 33%, while wood has about a 2% ash content when burned. Algae have a high water content requiring much energy to dry the algae before being able to properly use it. More research is being done with
anaerobic digestion Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the ferm ...
, which is the most promising practice to extract energy from ''Laminaria''. There are still barriers to overcome before moving forward with anaerobic digestion, such as its cost per
kwh A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy: one kilowatt of power for one hour. In terms of SI derived units with special names, it equals 3.6 megajoules (MJ). Kilowatt-hours are a common bill ...


Metal absorption

The ability of laminaria, along with other
brown algae Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and p ...
, to absorb
heavy metals upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as ...
is a current area of interest regarding their use to remove heavy metals from wastewater. Laminaria has been shown by recent research to have a favorable mannuronic/guluronic acid residues ratio (M/G ratio) for heavy metal absorption in its alginate. This M/G ratio is the ratio between the L-gluronate (G) and D-mannuronate (M) in the alginate, a natural anionic polymer that is found in all brown algae. This alginate is able to form a gel that contains carboxyl groups that can bind heavy metal cations such as , , and , thereby allowing these metals to be removed from wastewater.


Predator

''
Coelopa frigida ''Coelopa frigida'' is a species of seaweed fly or kelp fly. It is the most widely distributed species of seaweed fly. It can be found on most shorelines in the temperate Northern Hemisphere. Other species of seaweed flies include ''Coelopa nebul ...
'' and related flies from the genus ''Coelopa'' are known to feed, mate, and create habitats out of different species of ''Laminaria''. This is of particular notice when the ''Laminaria'' is stranded on the beach and not when it is submerged under seawater. With increasing amounts of seaweed washing up on shores, there is an increasing recognition of ''Laminaria'' and their close pairing with ''Coelopa''.


Species

*'' Laminaria abyssalis'' A.B. Joly & E.C. Oliveira – South American Atlantic *'' Laminaria agardhii'' Kjellman – North American Atlantic  *'' Laminaria appressirhiza'' J. E. Petrov & V. B. Vozzhinskaya *''
Laminaria brasiliensis ''Laminaria'' is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relati ...
'' A. B. Loly & E. C. Oliveira *'' Laminaria brongardiana'' Postels & Ruprecht  *'' Laminaria bulbosa'' J. V. Lamouroux *'' Laminaria bullata'' Kjellman *''
Laminaria complanata ''Laminaria'' is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relativ ...
'' (Setchell & N. L. Garder) Muenscher *'' Laminaria digitata'' (Hudson) J. V. Lamouroux *'' Laminaria ephemera'' Setchell – Pacific of North America: From Vancouver to California  *''
Laminaria farlowii ''Laminaria'' is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relati ...
'' Setchell – Coast of the North American Pacific  *''
Laminaria groenlandica ''Laminaria'' is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relativ ...
'' – British Columbia *''
Laminaria hyperborea ''Laminaria hyperborea'' is a species of large brown alga, a kelp in the family Laminariaceae, also known by the common names of tangle and cuvie. It is found in the sublittoral zone of the northern Atlantic Ocean. A variety, ''Laminaria hyperbor ...
'' (Gunnerus) Foslie – Northeast Atlantic, Baltic Sea and North Sea. *'' Laminaria inclinatorhiza'' J. Petrov & V. Vozzhinskaya *'' Laminaria longipes'' Bory de Saint-Vincent, 1826 *'' Laminaria multiplicata'' J. Petrov & M. Suchovejeva *'' Laminaria nigripes'' J. Agardh *''
Laminaria ochroleuca ''Laminaria ochroleuca'' is a large kelp, an alga in the order Laminariales.Bunker, F.StP,D., Brodie, J.A., Maggs, C.A. and Bunker, A.R. 2017. ''Seaweeds of Britain and Ireland. Second Edition.'' Wild Nature Press, Plymouth, UK. They are common ...
'' Bachelot de la Pylaie *''
Laminaria pallida ''Laminaria pallida'', the split-fan kelp, is a species of large brown seaweed of the class Phaeophyceae found from Danger Point on the south coast of South Africa to Port Nolloth, Tristan da Cunha and Gough islands in the Atlantic and Île S ...
'' Greville – South Africa,  Indian Ocean, Canary Islands and Tristán da Cunha  *''
Laminaria platymeris ''Laminaria'' is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relativ ...
'' Bachelot de la Pylaie *'' Laminaria rodriguezii'' Barnet *''
Laminaria ruprechtii ''Laminaria'' is a genus of brown algae, brown seaweed in the order Kelp, Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery L ...
'' (Areschoug) Setchell *'' Laminaria sachalinensis'' (Miyabe) Miyabe *''
Laminaria setchellii ''Laminaria'' is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relati ...
'' P. C. Silva *'' Laminaria sinclairii'' (Harvey ex J. D. Hooker & Harvey) Farlow, Anderson & Eaton
North American North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the ...
Pacific coast  *'' Laminaria solidungula'' J. Agardh *'' Laminaria yezoensis'' Miyabe


References


External links


Laminaria
at
AlgaeBase AlgaeBase is a global species database of information on all groups of algae, both marine and freshwater, as well as sea-grass. History AlgaeBase began in March 1996, founded by Michael Guiry. Text was copied from this source, which is avail ...
{{Taxonbar, from=Q310748 Laminariaceae Marine biota of Asia Marine biota of Europe Marine biota of North America Biota of the Mediterranean Sea Flora of the Pacific Laminariales genera